Driving circuits for electronic clocks and watches

ABSTRACT

An electromechanical driving circuit for use in electronic clocks and watches adapted to supply electromagnetic pulses produced in two coils S1 and S2 arranged between permanent magnets secured to an oscillatory moving body such as a balancing wheel of an electronic clock or watch. Provision is made of a single condenser Ca adapted to be supplied with an electric current relating to induced voltages produced in the coils S1 and S2 when transistors whose collectors are connected to the coils S1 and S2, respectively, are made alternately conductive.

States atent 1 Kanazawa et al.

[4 1 May 20, 1975 DRllVING CIRCUITS FOR ELECTRONIC CLOCKS AND WATCHES [75] Inventors: Toyoji Kanazawa, Tachikawa;

Makoto Yoshida, Tokorozawa, both of Japan [73] Assignee: Citizen Watch Co., Ltd., Tokyo,

Japan [22] Filed: July 31, 1973 [21] App]. No.: 384,388

[30] Foreign Application Priority Data Aug. 10, 1972 Japan 47-79519 [52] U.S. Cl 58/23 A; 58/28 A; 318/129; 331/116 M [51] Int. Cl G04c 3/04; HOlh 47/24; H03b 5/36 [58] Field of Search 58/23 A, 28 A, 28 V; 331/116 M; 318/129 [56] References Cited UNITED STATES PATENTS 3,407,344 10/1968 Bansho 58/28 R X 3,481,138 12/1969 Futagawa et a] 58/28 Primary Examiner-Edith Simmons Jackmon Attorney, Agent, or Firm-Ernest G. Montague; Karl F. Ross; Herbert Dubno [57] ABSTRACT An electromechanical driving circuit for use in electronic clocks and watches adapted to supply electromagnetic pulses produced in two coils S and S arranged between permanent magnets secured to an oscillatory moving body such as a balancing wheel of an electronic clock or watch. Provision is made of a single condenser Ca adapted to be supplied with an electric current relating to induced voltages produced in the coils S and S when transistors whose collectors are connected to the coils S and S respectively, are made alternately conductive.

8 Claims, 8 Drawing Figures PATENTEDIAYZOIBYS $884,032

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PATENTED 3,884,032

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SHEET 3 OF 3 DRIVING CIRCUITS FOR ELECTRONIC CLOCKS AND WATCHES This invention relates to electromechanical driving circuits for use in electronic clocks and watches which continuously drive an oscillatory moving body by means of a small current supply source such as an electric battery etc. and, more particularly, to an electromechanical driving circuit which can reliably supply electromagnetic pulses to an electromechanical driven system of electronic clocks and watches.

A principal object of the invention is to provide an electromechanical driving circuit which can improve the driving efficiency of a conventional electromechanical circuit which makes use of a small current supply source, which can incorporate circuit component parts of intergrated circuit, which can be manufactured in a simple and easy manner and is small in size, and which can improve the space factor in an electronic clock and watch.

A conventional electromechanical driving circuit heretofore used and adapted to drive, for example, an oscillatory magnet type balancing wheel of an electronic wrist watch will be described with reference to FIGS. la and 1b. In FIGS. 1a and 1b, C designates an electromechanical driving circuit and E an electric current supply source. Reference numeral 1 designates a plurality of permanent magnets, 2 shows a balancing wheel a part or all of which is made of a ferromagnetic material and 3 designates a shaft of the balancing wheel 2. The balancing wheel 2 is secured to the shaft 3 and adapted to be oscillatorily moved together with the shaft 3. Numeral 4 is a hair spring adapted to oscillatory move the balancing wheel 2, and 5 shows a substrate and 6 a supporting frame secured to the substrate 5. The upper and lower ends of the shaft 3 are journaled in the substrate 5 and the frame 6, respectively. S and S designate coils arranged between the permanent magnets 1 which are arranged in diametric opposition and are of opposite polarities. An induced voltage 2 produced in the coil S is opposite in polarity to an induced voltage e produced in the coil S at the same instant as shown in FIG. 2.

In FIG. 3 is shown one example of the conventional electromechanical driving circuit C in which one of the terminals of the coils S is connected through a condenser Ca to the base of a transistor Tr, while one of the terminals of the coil S is connected to the collector of the transistor Tr. Between the other terminal of the coil S and the emitter of the transistor Tr is connected an electric current supply source E. The transistor Tr serves as a switch for opening and closing a circuit including the coil S by the induced voltage produced in the coil S and applied through the condenser Ca to the base of the transistor Tr. The opening and closing time of the switching transistor Tr is controlled by the electric charge accumulated in the condenser Ca and by a time constant determined by the condenser Ca and a resistor R connected in parallel thereto. As a result, an intermittent current flows through the coil S As seen from the above, in this circuit the operation of the coil S is different from that of the coil S That is, the coil S which operates as a control coil can not be used in place of the coil S which operates as a driving coil unless the connection of the circuit is changed. Thus, a driving force which can continue the oscillatory movement of the balancing wheel 2 is produced by the coil S only once a period.

In FIG. 4 is shown another example of the conventional electromechanical driving circuit C in which one of the terminals of a coil S and one of the terminals of a coil S are connected through junction points A and B to the collectors of transistors Tr and Tr respectively, while the other terminals of the coils S and S are connected through an electric current supply source E to the emitters of the transistors Tr, and Tr The junction point A is connected through a condenser Ca to the base of the transistor Tr while the junction point B is connected through a condenser Ca to the base of the transistor Tr This circuit arrangement is a multivibrator in which self-relaxation oscillation is capable of passing a current through each of the coils S and S even when the oscillatory motion of the balancing wheel 2 is stopped, that is, even when the induced voltage is not produced in each of the coils S and S thereby self-sustaining the oscillatory movement of the balancing wheel 2. A positive induced voltage e produced in the coil S makes the transistor Tr conductive, while a positive induced voltage e produced in the coil S makes the transistor Tr, conductive. That is, if the coil S becomes operative as the control coil, the coil S is operated as the driving coil and conversely if the coil S becomes operative as the control coil, the coil S is operated as the driving coil, and as a result, the circuit shown in FIG. 4 is capable of producing driving forces twice during each period which can continue the oscillatory movement of the balancing wheel 2. If a current i flows through the coil S, or and an induced voltage e is produced therein, the effective power of the electromechanical driving circuit C shown in FIG. 4 is given by ei. The induced voltage e or e produced in the coil S, or changes as a function of time t as shown in FIG. 2. It is most preferable to make a current flow through the coil S, or S at that instant which is near the instant at which the largest induced voltage 2 or e is produced. If the driving force produced by the circuit shown in FIG. 3 is assumed to be equal to the driving force produced by the circuit shown in FIG. 4, a current must flow through the circuit shown in FIG. 3 from that instant which is closest to the instant at which the largest induced voltage is produced since the driving force is produced once a period. The circuit shown in FIG. 4, however, is capable of making the current flow at the instant when the induced voltage e is high. As a result, the driving efficiency of the circuit shown in FIG. 4 is higher than that of the circuit shown in FIG. 3. But, the circuit shown in FIG. 4 has the disadvantage that-the component parts constituting the circuit are large in number. This is a vital defect in a wrist watch whose space, in which all of these component parts are contained, is limited. Particularly, an electromechanical driving circuit adapted to operate the balancing wheel etc. in a low frequency has to utilize a condenser Ca which is large in capacity and size. The use of such a condenser Ca results in a difficulty in the manufacture of the electromechanical driving circuit.

A primary object of the invention, therefore, is to provide an electromechanical driving circuit for use in clocks and watches, which can incorporate all of component parts into a semiconductor integrated circuit so as to reduce the condenser Ca in capacitance and in size without neglecting any advantage of the conven- 3 tional electromagnetic driving circuit as shown in FIG. 4.

In general, the dimensions of the circuit elements such as transistor, resistor, diode etc. which can easily be incorporated into the integrated circuit can be made small by comparison with the dimensions of the condenser Ca. It might be considered that the circuit consisting, for example, of transistor, resistor, diode etc. would be of complex in construction. But, such disadvantages of the complex circuit is minor when compared with the advantage obtained by the reduction in size and capacitance of the condenser Ca.

As will hereinafter be described, the electromechanical described, the electromechanical driving circuit according to the invention takes into consideration the construction of the semiconductor integrated circuit so that the resistor designated by R and the transistor designated by Tr for ease of illustrating the operation of circuit represent any other circuit elements.

The invention makes use of the basic circuit operation that can produce the driving force twice a period owing to the above mentioned reasons. But the arrangement and operation of the circuit per se according to the invention are entirely different from those of the conventional circuit shown in FIG. 4.

The invention will now be described with reference to the accompanying drawings, in which:

FIG. 1a is a sectional view illustrating a relation between a balancing wheel of an electronic watch and a circuit for driving the balancing wheel;

FIG. lb is plan view of the part shown in FIG. 1;

FIG. 2 diagrammatically illustrates a relation between the operation of the balancing wheel shown in FIGS. 1a and 1b and induced voltages produced in the coils S and S FIGS. 3 and 4 are conventional driving circuit diagrams; and

FIGS. 5, 6 and 7 are driving circuit diagrams each embodying the invention.

In FIG. is shown a first embodiment of the electromechanical driving circuit according to the invention whose arrangement of component parts and operation thereof will now be described. In the present embodiment, one of the terminals of a coil S is connected through a junction point A to the collector of a transistor Tr while one of the terminals of a coil S is connected through a junction point B to the collector of a transistor Tr The other terminals of the S and S are connected through an electric current supply source E to the emitters of the transistors Tr and Tr An induced voltage produced at the junction point A is opposite in polarity to that produced at the junction point B as described above. The junction points A and B are connected to the emitters of transistors Tr and Tr,,, respectively, whose bases are connected through a common resistor R to the electric current supply source E. The collectors of the transistors Tr and Tr are connected in common to a junction point C. Between a junction point D and the junction point C are connected in parallel a condenser Ca and a resistor R The bases of the transistors Tr and Tr are connected through the junction points A and B to the coils S and 8;, respectively, while the emitter of the transistor Tr is connected to the base of the transistor Tr and the emitter of the transistor Tr is connected to the base of the transistor Tr The circuit shown in FIG. 5 can operate as follows. When the electric potential at the junction point A caused by the induced voltage e produced in the coil S causes the transistor Tr to shift from its nonconductive region to its active or conductive region, the electric potential at the junction point B caused by the induced voltage e produced in the coil S causes the transistor Tr to shift further to its nonconductive region. As a result, the electric potential at the junction point A only is transmitted to the junction point C. The electric potential at the junction point A also causes the transistor Tr to shift toward its active region and is transmitted through the transistor Tr to the base of the transistor Tr so as to make it conductive, and as a re sult, a current supplied from the electric current supply source E flows through the coil S If the potential at the junction point B causes the transistor Tr to shift toward its active region,'a current supplied from the electric current supply source E flows through the coil 8,. Thus, the circuit shown in FIG. 5 receives a signal from the coil S so as to make a current flowing through the coil S and receives a signal from the coil S so as to make a current flowing through the coil S these operations being effected alternately. As a result, the circuit shown in FIG. 5 operates to produce a driving force twice a period. Both the signal delivered from the coil S and the signal delivered from the coil S are transmitted through the junction points C-D and the transistors Tr and Tr to the transistors Tr and Tr,, respectively, to charge the condenser Ca. Thus, the electric charge charged in the condenser Ca and the change of the electric potential across the junction points C-D relative to a time constant determined by the condenser Ca and the resistor R become a threshhold voltage of the transistors Tr, and Tr which can control the time at which the driving force is produced and can control the amplitude of the signals delivered from the coils S and S respectively.

Representative numerical values of the component parts of the embodiment shown in FIG. 5 are as follows.

S and S 12 microns in diameter, 1500 turns, 3 K0.

in resistivity R 1 MD. in resistivity R 10 MO in resistivity C 0.1 pF in capacitance.

In FIG. 6 is shown a second embodiment of the electromechanical driving circuit according to the invention whose arrangement of component parts and operation thereof will now be described. In the present embodiment, one of the terminals of a coil S is connected through a junction point A to the collector of a transistor Tr while one of the terminals of a coil S is connected through a junction point B to the collector of a transistor Tr The other terminals of the coils S and S are connected through an electric current supply source E to the emitters of the transistors Tr and Tr An induced voltage produced at the junction point A is opposite in polarity to that produced at the junction point B as described above. The junction points A and B are connected to the emitters of transistors Tr and Tr respectively, whose bases are connected in common to a junction point C which is connected through a condenser Ca, which electrically represents one condenser, to one of the terminals of an electric current supply source E. In parallel with the condenser Ca is connected a resistor R so as to determine a time constant. The collector of the transistor Tr, is connected through a resistor R to the base of the transistor Tr while the collector of the transistor is connected through a resistor R to the base of the transistor Tr The resistance values of these resistors are made larger than zero. This is determined by design based on the characteristic of the transistor Tr Tr etc.

The operation of the circuit shown in FIG. 6 is as follows. If the electric potential at the junction point A deliversed from the coil S causes the transistor Tr, to shift from its nonconductive region to its active region, the induced voltage in the coil S causes the transistor Tr to shift its nonconductive region further toward its more intensively nonconductive region. As a result, only the electric potential at the junction point A results in a flow of current from the condenser Ca to the electric current supply source E. In addition, the transistor Tr becomes conductive so that a current flows from the electric current supply source E to the coil S If the electric potential at the junction point B causes the transistor Tr to shift to its active region, a current is supplied from the electric current supply source E to the coil S Thus, the circuit shown in FIG. 6 is operated such that arrival of the signal from the coil 8, causes a current flow through the coil S and that arrival of the signal from the coil S causes a current flow through the coil 8,, and as a result, the circuit as a whole is operated so as to produce the driving force twice a period. Since both the signal delivered from the coil S and the signal delivered from the coil S flow from the condenser Ca to the electric current supply source E, the electric charge accumulated in the condenser Ca and the charge in time of the electric potential produced at the junction point C and determined by the time constant of the condenser Ca and the resistor R become a threshhold voltage of the transistors Tr, and Tr and hence become a threshhold voltage of the transistor Tr and Tr The threshhold voltage is capable of controlling the timing and the amplitude of the current for producing the driving force and flowing through the coils S and S Representative numerical values of the component parts of the embodiment shown in FIG. 6 are as follows.

R5 Mo 6 500 m 1 500 m Ca 0.1 pF

In FIG. 7 is shown a third embodiment of the electromagnetic driving circuit according to the invention whose arrangement of component parts and operation thereof will now be described. In the present embodiment, one of the terminals of a coil S is connected through a junction point A to the collector of a transistor Tr while one of the terminals of a coil S is connected through a junction point B to the collector of a trnsistor Tr The other terminals of the coils S and S are connected through an electric current supply source E to the emitters of the transistors Tr and Tr respectively. An induced voltage produced at the junction point A is opposite in polarity to that produced at the junction point B as described above. Thejunction points A and B are connected to the emitters of transistors Tr and Tr respectively, whose bases are connected through the collector-emitter paths of transistors Tr and Tr in common to a junction point C which is connected through a condenser Ca, which electrically represents one condenser, to one of the terminals of the electric current supply source E. In parallel with the condenser Ca is connected a resistor R to determine a time constant. The collector of the transistor Tr is connected through a resistor R to the base of the transistor Tr while the collector of the transistor Tr is connected through a resistor R to the base of the transistor Tr The resistance values of these resistors are made larger than zero. This is determined by design based on the characteristic of the transistors Tr Tr etC.

Provision is made of a discharging circuit for the electric potential at the junction point C and consisting of transistors Tr and Tr The junction point C is connected through a resistor R to the base of the transistor Tr whose emitter-collector path is connected through the base-emitter path of the transistor Tr across the electric current supply source E. The collector of the transistor Tr is connected to the base of the transistor Tr whose collector is connected to a junction point between the resistor R and the base of the transistor Tr while the emitter of the transistor Tr is connected to the emitters of the transistors Tr, and Tr The operation of the circuit shown in FIG. 7 is as follows. If the electric potential at the junction point A becomes high owing to the induced voltage produced at the coil S the electric potential at the junction point B becomes low. In this state the transistor Tr is shifted from its nonconductive region to its active region, and as a result, the transistor Tr is shifted to its active region. Thus, the condenser Ca is charged by a current flowing through the base-emitter of the transistor Tr and by a current flowing through the emitter-base of the transistor Tr and the collector-emitter of the transistor Tr If the transistor Tr becomes conductive, a current flows through its emitter-collector path and the resistor R to the base of the transistor Tr and as a result, the transistor Tr becomes conductive and hence a current is supplied from the electric current supply source E to the coil S If the electric potential at the junction point B becomes high and the electric potential at the junction point A becomes low owing to the induced voltages produced in the coils S and S the transistors Tr and Tr are shifted to their active regions and become conductive, respectively. Thus the condenser Ca is charged by a current flowing through the base-emitter path of the transistor Tr and by a current flowing through the emitter-base path of the transistor Tr and the collector-emitter path of the transistor Tr If the transistor Tr becomes conductive, a current flows through its emitter-collector path and the resistor R to the base of the transistor Tr and as a result, the transistor Tr becomes conductive and hence a current is supplied from the current supply source E to the coil S Thus, also in the present embodiment, the signal delivered from the coil S causes a current flow through the coil S while the signal delivered from the coil S causes a current flow through the coil S and as a result, the circuit as a whole operates to produce a driving force for oscillatorily moving the balancing wheel twice a period.

In addition, the condenser Ca is charged twice a period. The electrical potential at the junction point C becomes high when the condenser Ca is charged and is decreased when the charging of the condenser Ca becomes ceased. The decrease of the electrical potential at the junction point C is changed in function with time in dependence with the time constant determined by the condenser Ca and the resistor R The function and effect of the condenser Ca are the same as those of the condenser Ca described with the embodiments shown in FIGS. and 6.

In the present embodiment, the discharging circuit consisting of transistors Tr and Tr is connected across the condenser Ca for the purpose of improving the property of starting the oscillatory operation of the circuit.

In general, the lower the electric potential at the junction point C the more easily the transistor Tr or Tr, becomes conductive and hence the property of starting the oscillatory operation of the circuit can be improved. But, the higher the electric potential at the junction point C the lesser the dark current flows and hence the driving efficiency of the circuit can'be improved.

As stated hereinbefore, the electric potential at the junction point C is discharged in function exponentially with the time constant determined by the condenser Ca and the resistor R If this time constat is large, it takes a long time to discharge the electric potential at the junction point C. Under such condition, if the amplitude of the oscillatory operation of the circuit becomes suddenly decreased owing to exterior disturbances etc., it takes a long time to restore the amplitude thus decreased to its normal amplitude, thereby degrading the property of starting the oscillatory operation of the circuit.

In the embodiment shown in FIG. 7, provision is made of the discharging circuit consisting of the transis'tors Tr, and Tr connected across the condenser Ca and which can operate when the electric potential at the junction point C becomes lower than a given level to expedite the rate of discharging the condenser Ca.

The discharging circuit shown in FIG. 7 will operate as follows.

If the electric potential at the junction point C is discharged by the time constant determined by the condenser Ca and the resistor R and reaches to a given potential, the transistor Tr becomes conductive. Thus, the transistor Tr becomes conductive, and as a result, the condenser Ca is discharged through the collectoremitter path of the transistor Tr Thus, it is possible to shorten the discharging time of the condenser Ca if compared with the discharging time determined by the time constant of the condenser Ca and the resistor R thereby considerably improving the property of starting the oscillatory operation of the circuit.

The resistor R connected between the junction point C and the discharging circuit can further improve the property of starting the oscillatory operation of the circuit.

Representative numerical values of the component parts of the embodiment shown in FIG. 7 are as follows.

R 10 MO.

Continued Ca 0.1 p.F 9 500 KO 10 500 KQ 11 500 KO The conductivity type of the transistor Tr may be changed from NPN type to PNP type or from PNP type to NPN type without affecting the operation of the circuit. In this case, however, care must be taken to charge the polarity of the electric current supply source E correspondingly.

The electromechanical driving circuit according to the invention has advantages that use may be made of only one condenser Ca for the purpose of controlling the amplitude of the current for producing the driving force and flowing through the coils S, and S that the efficiency for driving the balancing wheel can be improved; and that the transistor Tr and the resistor. R may be incorporated into an integrated circuit to provide a driving circuit or a balancing wheel of a wrist watch, which is extremely small in size and reliable in operation.

As stated hereinbefore, the embodiments shown in FIGS. 5, 6 and 7 can produce the driving force twice a period. In this case, an induced current flows through the condenser Ca twice a period. As a result, the condenser Ca operates for a period which is equivalent to half the operating period of the condenser Ca used in the conventional circuits shown in FIGS. 3 and 4, and as a result, the capacity of the condenser Ca in the circuits shown in FIGS. 5, 6 and 7 may be made smaller than half the capacity of the condenser Ca in the circuits shown in FIGS. 3 and 4. This feature of the invention renders it possible to make the wristwatch thin in thickness and small in size. In addition, the circuits shown in FIGS. 5, 6 and 7 have a self-starting property to be described later.

In the circuits shown in FIGS. 5, 6 and 7, the signal is transmitted in a direct current connection, while the operation is effected in an alternating current connection. Thus, the circuits shown in FIGS. 5, 6 and 7 operate as a multivibrator. For example, in the circuit shown in FIG. 6, the transistor Tr; or Tr becomes conductive owing to the presence of component parts which are slightly different in design values and owing to electrical shocks occurring at the time of switching in the electric current supply source E, thereby producing the driving force. The driving force is once produced, the circuit shown in FIG. 6 will continuously operate as described above.

The invention has been described in case of applying it to an electromechanical driving circuit for use in electronic clocks and watches whose balancing wheel is provided with magnets associated with separate coils, respectively. The invention is not limited to such circuit and may be applied to any type of electromechanical driving circuit.

What is claimed is:

1. An electromechanical driving circuit for use in electronic clocks and watches comprising an oscillatory moving body, a plurality of permanent magnets secured to said oscillatory moving body at its diametrically opposite parts, two coils S and S each arranged between said permanent magnets and adapted to be moved relative to said permanent magnets, which comprises first transistors with emitters earthed and collectors connected to said coils S and S respectively, and a condenser Ca operatively connected through second transistors to junction points between the collectors of said first transistors and said coils S and S respectively, and adapted to be supplied with an electric current relating to induced voltages produced in said coils S and S whereby said first transistors are made alternately conductive in response to said electric current.

2. An electromechanical driving circuit for use in electronic clocks and watches claimed in claim 1 which further comprises a resistor connected in parallel with said condenser Ca.

3. An electromechanical driving circuit for use in electronic clocks and watches as claimed in claim 1 wherein said condenser Ca is connected to a junction point between the same electrodes respectively of said second transistors.

4. An electromechanical driving circuit for use in electronic clocks and watches comprising an oscillatory moving body,

permanent magnets secured to said oscillatory moving body at its diametrically opposite position relative to each other,

two coils each arranged between said permanent magnets and adapted to be moved relative to said permanent magnets,

an electric current supply source,

first transistors having grounded emitters and having collectors connected through first junction points to said coils, respectively,

resistors,

second transistors having collectors connected through said resistors, respectively to the bases of said first transistors, respectively, and having emitters connected to said first junction points, respectively, and having bases operatively connected to a common junction point, and

a parallel circuit including a condenser and another resistor,

one end of said parallel circuit being connected to said common junction point.

5. An electromechanical driving circuit for use in electronic clocks and watches claimed in claim 4 which further comprises a discharging circuit connected across said condenser Ca and adapted to be operated when the discharging voltage of said condenser Ca is decreased to a level lower than a given level.

6. The electromechanical driving circuit, as set forth in claim 7, further comprising third transistors having bases, respectively, connected to said first junction points,

the bases of said second transistors are connected through base-emitter paths respectively, of said third transistors, respectively, to said common junction point,

said parallel circuit is connected between said common junction point and the emitters of said first transistors.

7. The electromechanical driving circuit, as set forth in claim 4, wherein said second transistors with bases are connected in common through said common junction point, and the other end of said parallel circuit is connected to the ground. I 8. The electromechanical driving circuit, as set forth in claim 6, which further comprises a discharging circuit including,

a nother transistor having a collector-emitter path connected across said condenser, and

a further transistor having a base connected to the collector of said other transistor, and having a collector connected to the base of said other transistor and having an emitter connected to another junction point between said two coils and said electric current supply source. 

1. An electromechanical driving circuit for use in electronic clocks and watches comprising an oscillatory moving body, a plurality of permanent magnets secured to said oscillatory moving body at its diametrically opposite parts, two coils S1 and S2 each arranged between said permanent magnets and adapted to be moved relative to said permanent magnets, which comprises first transistors with emitters earthed and collectors connected to said coils S1 and S2, respectively, and a condenser Ca operatively connected through second transistors to junction points between the collectors of said first transistors and said coils S1 and S2, respectively, and adapted to be supplied with an electric current relating to induced voltages produced in said coils S1 and S2, whereby said first transistors are made alternately conductive in response to said electric current.
 2. An electromechanical driving circuit for use in electronic clocks and watches claimed in claim 1 which further comprises a resistor connected in parallel with said condenser Ca.
 3. An electromechanical driving circuit for use in electronic clocks and watches as claimed in claim 1 wherein said condenser Ca is connected to a junction point between the same electrodes respectively of said second transistors.
 4. An electromechanical driving circuit for use in electronic clocks and watches comprising an oscillatory moving body, permanent magnets secured to said oscillatory moving body at its diametrically opposite position relative to each other, two coils each arranged between said permanent magnets and adapted to be moved relative to said permanent magnets, an electric current supply source, first transistors having groundEd emitters and having collectors connected through first junction points to said coils, respectively, resistors, second transistors having collectors connected through said resistors, respectively to the bases of said first transistors, respectively, and having emitters connected to said first junction points, respectively, and having bases operatively connected to a common junction point, and a parallel circuit including a condenser and another resistor, one end of said parallel circuit being connected to said common junction point.
 5. An electromechanical driving circuit for use in electronic clocks and watches claimed in claim 4 which further comprises a discharging circuit connected across said condenser Ca and adapted to be operated when the discharging voltage of said condenser Ca is decreased to a level lower than a given level.
 6. The electromechanical driving circuit, as set forth in claim 7, further comprising third transistors having bases, respectively, connected to said first junction points, the bases of said second transistors are connected through base-emitter paths respectively, of said third transistors, respectively, to said common junction point, said parallel circuit is connected between said common junction point and the emitters of said first transistors.
 7. The electromechanical driving circuit, as set forth in claim 4, wherein said second transistors with bases are connected in common through said common junction point, and the other end of said parallel circuit is connected to the ground.
 8. The electromechanical driving circuit, as set forth in claim 6, which further comprises a discharging circuit including, a nother transistor having a collector-emitter path connected across said condenser, and a further transistor having a base connected to the collector of said other transistor, and having a collector connected to the base of said other transistor and having an emitter connected to another junction point between said two coils and said electric current supply source. 